Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy of wind using known foil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
Wind turbines, and the blades in particular, are prone to lightning strikes. Current lighting protection systems typically include a main, internal down conductor configured in the blade and connected to the wind turbine's ground path. Several individual lightning receptors (generally less than 50 mm in diameter) are located on the external surface of the blade (pressure or suction side surfaces) and are connected by a wire or cable to the down conductor. With this design, however, the “protected” area of the blade (receptor area) is relatively small compared to the overall area of the blade, leaving much of the blade prone to ungrounded lightning strikes. In addition, a lightning strike on a receptor may result in substantial damage to the primary blade structure surrounding the receptor, which involves a significant repair procedure requiring shut down of the wind turbine for removal, repair, or replacement of the blade.
Thus, an improved lightning strike protection system for wind turbine rotor blades would be beneficial, particularly a system that offers increased surface area coverage without contributing significantly to the overall weight and complexity of the blade and while facilitating relatively low cost and easier repair procedures after an actual lightning strike on the blade.